[gmx-users] pressure scaling more than 1%

[Sebastian Waltz]

Hi all,

my simulation runs well for the first 700000 steps with a
step size of 0.001ps and when I get the warning that the
pressure scaling is more than 1% every 10000 step or so.
So, is my tau_p of 0.2 to small or is the equillibration
not done well enough.
I am simulating a small peptide in CHCl3 with an handmade
CHCl3 model. 

 title        = ttt
cpp                 =  /lib/cpp
include             = -I../top
constraints         =  none
;define              =  -DFLEX_SPC
;define              =  -DPOSRES			; for possition
restraints
integrator          =  md			
emtol               =  100.0 			
emstep              =  0.005			
dt                  =  0.001    		; ps !
nsteps              =  2000000  		; total 2 ns
nstcomm             =  1			

nstxout             =  0			
nstvout             =  0			
nstfout             =  10			
nstlog              =  0			
nstenergy           =  10			
nstxtcout           =  10

xtc_grps            = Protein+PTS+AIC 

nstlist             =  5			
ns_type             =  grid			
rlist               =  1.2			

coulombtype         =  PME			
rcoulomb            =  1.2			
rvdw                =  1.2			
fourierspacing      =  0.12			
pme_order           =  4			
optimize_fft        =  yes

Tcoupl              =  berendsen
tc-grps             =  Protein+PTS+AIC CHCl3
tau_t               =  0.1 0.1 
ref_t               =  300 300

energygrps          =  Protein+PTS+AIC CHCl3

Pcoupl              =  berendsen
tau_p               =  0.2
compressibility     =  5.4e-5
ref_p               =  1.0

gen_vel             =  yes
gen_temp            =  300
gen_seed            =  913529


Thanks